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Slope on track side embankment


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  • RMweb Gold

Hi

 

Appreciate that to an extent this is a "piece of string"question but I'd be interested in views. Before attempting to build a more ambitious layout, I'm looking to develop my abilities (currently next to non-existent) in the scenery department. My concept is, on a c4' by 2' board to build a small diorama. Originally I had contemplated building something on the level but reading comments across different threads here and in magazines, adding depth massively improved the look of whatever you produce. Therefore, I thought I'd put a line on an embankment through a semi-rural scene.

 

In particular, I've been inspired by a picture that's fascinated me since childhood from Awdry's Stepney the Bluebell engine... Within that book, there's a fairly improbable story of a train stopping at a station by a cricket match into which the ball is hit and carried away. The story is accompanied by a fine picture of a train about to cross a bridge over a road with the cricket pitch on one side. With fine cricket scenes available, another or my passions, it struck me a fine picture to recreate in in miniature having several elements that could be interesting to model. I'll embellish the picture with a car park and that other essential element to a cricket club of a nearby pub!

 

My key question is from the track bed to baseboard level, is there a rule of thumb for how steeply I can slope that embankment? I'm assuming that trial and error is as good a way as any to see what looks "right"

 

Many thanks

 

David

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Victorian appreciation of Soil Mechanics / Geotechnical Engineering was non existent. Embankments were tipped, and would therefore stand at the angle of repose and then consolidated by first letting horses etc tamp things down and then running trains slowly while things settled. Thus embankments are much steeper than you find on modern works such as motorways. Thirty degrees from the vertical is not impossible, depends on the type of material. In a model, you can get away with things which would not occur in practice. I once built a station approach ramp at 1 in 6. It looked ok but in practice it would have been horrendous. I suggest you build a mock up out of cardboard or whatever is cheap and see what it looks like.

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And it depends very strongly on the makeup of the terrain. Loose soil has to have a lesser slope than clay, which has to be less than rocky stuff etc etc.

 

If they got it wrong, landslips resulted....and you then needed Jo from the Railway Children to help.

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John Miles

 

I would be really interested to learn if there is anything to support the idea that Victorian era engineers had little or no understanding on the subject?

 

Many of the great civil engineering projects were built during the Victorian era. The difference of course is that they could not have predicted the advancement of technology that would have used the aforementioned civil engineering.

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  • RMweb Premium

In particular, I've been inspired by a picture that's fascinated me since childhood from Awdry's Stepney the Bluebell engine... Within that book, there's a fairly improbable story of a train stopping at a station by a cricket match into which the ball is hit and carried away. The story is accompanied by a fine picture of a train about to cross a bridge over a road with the cricket pitch on one side. With fine cricket scenes available, another or my passions, it struck me a fine picture to recreate in in miniature having several elements that could be interesting to model. I'll embellish the picture with a car park and that other essential element to a cricket club of a nearby pub!

 

While the good Reverends story may have been fictional, Stepney's owners have the ability to bring it to life:-

 

https://www.justgiving.com/Bluebell-Railway-Cricket/

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  • RMweb Gold

Thanks - and fantastic there's a real life prototype! My son and i are big fans of the Bluebell

 

Inputs above very much appreciated. I suspect even in Victorian times, minimising land take from third parties was still objective which would push towards steeper slopes. Think I'll go for some trial and error and see what happens

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I know of one fairly steep embankment that passes such a cricket ground (and a football ground as well) - Dorchester to Weymouth after the two tracks from Dorchester West and Dorchester South join (I believe now occupied by the Tesco).

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  • RMweb Gold

If you want a cricket match by a railway line try this - about three quarters of the way through.

 

 

Chris Turnbull

Thanks - that's an excellent clip. Rather than do a fully cricket pitch, my thinking is to do the edge and let the imagination do the rest of the work. Eg a widescreen with long-off stood to the side, scoreboard with scorers with pen, next man in sat outside pavilion. Cars in car park etc

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  • RMweb Premium

As a sometime practicing geotechnical engineer I make use of CIRIA Publication C504 – ‘Engineering in Glacial Tills’, NA Trenter, 1999.
 
The two tables below give observed side slopes respectively for cuttings and embankments in natural soils. Side slopes become flatter the closer you get to the south east of England. This follows from the geological history of the British Isles.
 
If embankments are engineered with crushed rock, cement or lime stabilised materials, processed industrial waste or reinforced earth then side slopes can be steepened - almost to 1:1 (45 degrees).
 
Historically some canal and railway cuttings in clay were made ‘artificially’ steeper by filling the excavation with combustible material (straw) and setting it on fire to bake the excavated surface.
 
Our ancestors knew a thing or two and as an aside if you thought that reinforced soil was a new invention, St David’s Cathedral in Wales and various Thames bridges were built on bales of wool to improve the bearing capacity of the soft soils below.

 

21354908741_8c073ba0a1_o.jpg

20723950384_9393d947a5_o.jpg

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  • RMweb Premium

Victorian appreciation of Soil Mechanics / Geotechnical Engineering was non existent. Embankments were tipped, and would therefore stand at the angle of repose and then consolidated by first letting horses etc tamp things down and then running trains slowly while things settled. Thus embankments are much steeper than you find on modern works such as motorways. Thirty degrees from the vertical is not impossible, depends on the type of material. In a model, you can get away with things which would not occur in practice. I once built a station approach ramp at 1 in 6. It looked ok but in practice it would have been horrendous. I suggest you build a mock up out of cardboard or whatever is cheap and see what it looks like.

I'm sure Georgian (George IV period) George Stephenson would be disappointed to hear your views of him and his Victorian successors, after he successfully built the Liverpool & Manchester Railway, across Chat Moss - a peat bog. Just for good measure he & his son Robert, built the Rocket. George also designed the Skew Bridge at Rainhill, which is still in use.

 

https://en.wikipedia.org/wiki/George_Stephenson#Liverpool_and_Manchester_Railway

 

Interesting about safety lamps too.

 

I'd say he had a fair idea, on how to design structures and equipment.

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Soil Mechanics requires the ability to calculate/identify a whole range of characteristics George Stephenson had no idea about. There is a whole difference in calculating the failure point via assessment and building something which has so high a factor of safety that what soil it was built of/ in is largely immaterial.

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  • RMweb Gold

Thanks - that's an excellent clip. Rather than do a fully cricket pitch, my thinking is to do the edge and let the imagination do the rest of the work. Eg a widescreen with long-off stood to the side, scoreboard with scorers with pen, next man in sat outside pavilion. Cars in car park etc

 

Good move. A full cricket field would need a much larger board.

 

I think it is Ancorton who do a rather nice laser-cut pavilion which would be ideal for cricket.

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John Miles

 

I would be really interested to learn if there is anything to support the idea that Victorian era engineers had little or no understanding on the subject?

 

Many of the great civil engineering projects were built during the Victorian era. The difference of course is that they could not have predicted the advancement of technology that would have used the aforementioned civil engineering.

 

From memory the only analytical method available in Victorian times was due to Rankin which was for a granular fill such as sand. Soil Mechanics only really got going in the thirties with the work of Terzaghi and Peck who made the important distinction between cohesive soils (e.g. clay) and materials such as sand and gravel. The theory of sllip circles and toe heave (many slips if you look at them have a large mound of earth pushed up at their toe). More recently there have been different analytical methods emerging from Cambridge but so far as I know, these have yet to find significant use in practice.

 

Just to really put the cat amongst the pigeons, the understanding of structural behaviour was also very limited in Victorian times.

 

Bomag gets ut right :-

 

Soil Mechanics requires the ability to calculate/identify a whole range of characteristics George Stephenson had no idea about. There is a whole difference in calculating the failure point via assessment and building something which has so high a factor of safety that what soil it was built of/ in is largely immaterial.

 

 

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  • RMweb Gold

Good move. A full cricket field would need a much larger board.

 

I think it is Ancorton who do a rather nice laser-cut pavilion which would be ideal for cricket.

Thanks - I'll look them up. I know metcalf do a card one but was thinking of the Langley one

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How much consolidation of embankments was done on UK railways? I ask because there doesn't seem to have been any done on North American railways when trestles were filled in. I've climbed up the fill created when this trestle was filled in

 

http://www.hankstruckpictures.com/pix/trucks/hank_rabe/2008/06-04/gerri_logan/01.jpg

 

and was amazed at how loose it was. My feet sank in at every step, and I slid back about one step for every two I took. OK, the trestle is still there within the fill, but the fill didn't seem substantial at all. Rather makes me question the overall strength of filled trestles. I know that if I bury timber in the yard, treated or even creosoted, it will rot reasonably quickly. So you have rotting timber within loose, uncompacted fill?

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The proof is in the pudding.

 

Many miles of track work is laid right on top of ground works from the Victorian or earlier periods. Even take the Settle & Carlisle. There's a well known viaduct there for example... built on top of a bog.

 

 

Just because engineers didn't use your table it doesn't mean they didn't know what they were doing.

 

 

As a comparison, take a 1860's sailing ship Master- he didn't have the same access to the technical manuals of a modern day Captain- but he knew his stuff. Astronomers, scientists, metallurgists, engineers... the list goes on.

 

I'm afraid your "lacked the formal documents thus lacked understanding" appraisal is not matching history. But you've said your bit. I've said mine. Leave it to others to judge who is right. (and if in doubt they can go and look for themselves.) 

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  • RMweb Premium

The proof is in the pudding.

 

Many miles of track work is laid right on top of ground works from the Victorian or earlier periods. Even take the Settle & Carlisle. There's a well known viaduct there for example... built on top of a bog.

 

 

Just because engineers didn't use your table it doesn't mean they didn't know what they were doing.

 

 

As a comparison, take a 1860's sailing ship Master- he didn't have the same access to the technical manuals of a modern day Captain- but he knew his stuff. Astronomers, scientists, metallurgists, engineers... the list goes on.

 

I'm afraid your "lacked the formal documents thus lacked understanding" appraisal is not matching history. But you've said your bit. I've said mine. Leave it to others to judge who is right. (and if in doubt they can go and look for themselves.) 

 

 

 

 

Here's another key quote from the page I provided a link to, earlier.

 

Regarding the battle for the mine safety lamps. "The experience gave Stephenson a lifelong distrust of London-based, theoretical, scientific experts".

 

 

Also.

 

"Stephenson was farsighted in realising that the individual lines being built would eventually be joined together, and would need to have the same gauge."

 

 

Brunel (obviously the target of that quote), as well as picking the wrong gauge, also designed a track construction method that was flawed and had to be completely replaced & also spent a lot of money, his own & shareholders, on atmospheric propulsion.

 

I think it has to be said, that without the work done by engineers, such as Stephenson & Brunel, such tables as previously quoted, couldn't have been compiled. Such is the nature of being a pioneer.

 

A big mistake of the early railways, was of the loading gauge, a bit bigger all round, especially the corners, would have been better. However of course, it was largely all done by hand, so when that is taken into account, provides a REASON.

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The proof is in the pudding.

 

Many miles of track work is laid right on top of ground works from the Victorian or earlier periods. Even take the Settle & Carlisle. There's a well known viaduct there for example... built on top of a bog.

 

 

Just because engineers didn't use your table it doesn't mean they didn't know what they were doing.

 

 

As a comparison, take a 1860's sailing ship Master- he didn't have the same access to the technical manuals of a modern day Captain- but he knew his stuff. Astronomers, scientists, metallurgists, engineers... the list goes on.

 

I'm afraid your "lacked the formal documents thus lacked understanding" appraisal is not matching history. But you've said your bit. I've said mine. Leave it to others to judge who is right. (and if in doubt they can go and look for themselves.) 

 

Derek

 

You seem to be confusing engineers and builders. The early Victorians may have been good builders but not good engineers, particularly for ground engineering. You have to get wait for something like the Tamar bridge to get something truly creative (the tubes in compression the chains in tension). Even with the late Victorian Fourth Bridge while the dead loads were spot on the wind loads weren't.

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